Technical Abstract:
Objective of study: The objective of this study was to describe antimicrobial resistance patterns of Salmonella spp. and non-type specific Escherichia coli isolated from the same animals and same environmental areas over time.
Materials and Methods: Sampling occurred at a local dairy over a 12 month period, at 8 week intervals. Samples were collected from animal feces (cows and calves), feed, drinking water, hospital milk, colostrums and alleyway flush water.
Results: Salmonella serotypes recovered from environmental and fecal samples collected from the same groups of animals differed. Salmonella serotypes were different between calved and cows. In addition, antimicrobial resistance patterns of both Salmonella and E. coli were different.
Conclusions: Based on our data, we conclude that under field conditions Salmonella and E. coli may not exchange genetic material as readily as previously suggested. These results may be partially due to effective biosecurity procedures on this particular dairy, avoiding cross-contamination between cow and calf-areas.